cancer-prevention

Green tea – A potential preservative for extending the shelf life of fresh mutton at ambient temperature (25 ± 2 °C)

Author: K.V. Kumudavally and H.S. Phanindrakumar and Aisha Tabassum and K. Radhakrishna and A.S. Bawa

This investigation was taken up to evaluate the feasibility of using green tea (GT) to extend the shelf life of fresh mutton, at ambient storage conditions (25 ± 2 °C and 85 ± 5% RH). The ethanolic extract of GT (GTE) was found to significantly inhibit (P < 0.01) spoilage microflora, including certain pathogens of acidulant treated mutton (pH 3.8) for up to 4 days. Application of GTE did not cause any deleterious change in sensorial and physical quality and the mutton was acceptable for up to 4 days. While the control samples showed initial signs of spoilage between 20 and 24 h and registered an increase in free fatty acids (FFA) from 1.24 g to 4.1 g/100 g lipid and biogenic amine index (BAI) from 0.27 mg to 4.63 mg/100 g mutton, at the end of two days of storage, the GTE treated sample showed FFA levels of 1.5 g/100 g lipid and BAI of 0.25 mg/100 g mutton at the end of the 4 days. GTE treatment could be effectively used to extend the shelf life of fresh mutton for up to 4 days in Indian climatic conditions, since it significantly (P < 0.01) inhibits the formation of these lipolytic and proteolytic degradation products, which are responsible for sensorial spoilage.

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Author: Sheng-Dun Lin and En-Hui Liu and Jeng-Leun Mau

The extracts were prepared from cold or hot brewed steaming green tea at different concentrations (2, 6, and 10%), its antioxidant properties studied and potential antioxidant components determined. The yields of hot water extracts (17.49–28.27%) were significantly higher than those of cold water extracts (11.72–14.70%). EC50 values in antioxidant activity determined by the conjugated diene method and reducing power were 2.19–3.10 and 0.22–0.28 mg/ml, respectively. EC50 values in scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radicals were 29.45–43.80 and 2.88–3.22 mg/ml, respectively. EC50 values in chelating ability on ferrous ions were 6.45–13.51 mg/ml. Contents of total phenols were 221.71–330.22 mg/g whereas those of total catechins in cold and hot water extracts were 135.05–193.14 and 161.57–195.05 mg/g, respectively. Based on the results obtained, hot water extracts were more effective in antioxidant activity and reducing power. However, cold water extracts were more effective in scavenging ability on DPPH and hydroxyl radicals, and chelating ability on ferrous ions. Summarily, the cold brewing method would be a new alternative way to make a tea.

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Author: Takashi Kuzuhara and Masami Suganuma and Hirota Fujiki

Green tea catechins have recently gained significant acceptance as a cancer preventive, and one of the important features of catechins is their interactions with various target molecules. We recently found a functional and structural similarity between catechins and chaperones: Stochastic conformational analysis in silico revealed numerous conformations of (−)-epigallocatechin gallate, (−)-epicatechin gallate and (−)-epigallocatechin, showing a unique flexibility and mobility of the catechin molecules and suggesting the significance of a galloyl group in conformational variation. Since these conformations result in interaction with various types of molecules, we think that green tea catechin induces cancer preventive activity mediated through a chaperone-like property.

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Author: M. Dumarey and A.M. van Nederkassel and E. Deconinck and Y. Vander Heyden

Nowadays fingerprinting is a generally applied technique for the identification and quality assessment of herbal products. In this study it was aimed to predict a quantitative property, the antioxidant capacity of green tea, from chromatographic fingerprints. Different linear multivariate calibration techniques, commonly applied on spectral data, were explored and compared. When the chromatograms were appropriately pretreated, all tested techniques were able to predict the total antioxidant capacity with a precision comparable to that of the reference method (Trolox equivalent antioxidant capacity assay). Stepwise multiple linear regression (MLR) however is less recommended because of inadequate variable selection. Principal components regression (PCR) also seems less preferable, because large variations not correlated with the total antioxidant capacity were also included in the model. This problem does not occur with partial least squares (PLS) models. Of all tested PLS methods, orthogonal projections to latent structures (O-PLS) was preferred because of its simplicity, reproducibility, good interpretability of the compounds’ contribution to the antioxidant capacity and its good predictive and describing abilities.

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Author: Manal E.A. Elhalwagy and Nevine S. Darwish and Enass M. Zaher

The ameliorative effect of daily administrated dose of green tea extract (60 mg polyphenols/animal/day) was investigated on albino rats Rattus norvegicus (150–180 gm) intoxicated with 1/30 and 1/60 LD50 fenitrothion organophosphate insecticide for 28 days. Blood samples were taken at 14 and 28 days for further biochemical parameters. Histopathological studies were carried out in the liver and kidney at the end of the experiment. Significant inhibition in plasma cholinesterase (ChE), a biomarker of Ops, was recorded. Damage in the liver and kidney tissues was observed and confirmed with elevation of plasma alanine aminotransferase (ALT), aspartate aminotaransferase (AST), albumin, urea and creatinine, as well as an elevation in the oxidative stress (OS) marker malondialdehyde (MDA). Decrease in total glutathione (GSH) content in erythrocytes and fluctuation in glutathione S-transferase (GST) activity in plasma was also observed. Green tea supplementation (60 mg/animal/day) partially counteracts the toxic effect of fenitrothion on oxidative stress parameters and repairs tissue damage in the liver and kidney, especially when supplemented to 1/60 LD50 intoxicated animals depending on the duration. It seems that enzyme and metabolite markers of these organs need more time to be restored to the control level.

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Author: Vilma Simões Pereira Panza and Elisabeth Wazlawik and Gustavo Ricardo Schütz and Leandro Comin and Karl Christian Hecht and Edson Luiz da Silva

Objective This study investigated the effects of the consumption of green tea (GT) for 7 d on biomarkers of oxidative stress in young men undergoing resistance exercise. Methods Fourteen subjects performed a bench press exercise (four sets, 10 to 4 repetitions) after undergoing a period without (control group) or with the intake of GT (GT group; 2 g of leaves in 200 mL of water, three times per day). Blood samples were obtained before and after exercise and analyzed for total antioxidant capacity (ferric reducing ability of plasma [FRAP]), total polyphenols, reduced glutathione (GSH), lipid hydroperoxide (LH) and thiobarbituric acid–reactive substances, creatine kinase (CK), aspartate aminotransferase (AST), xanthine oxidase (XO), hypoxanthine, and uric acid (UA). Results In the control group, exercise did not affect the values of LH, thiobarbituric acid–reactive substances, and FRAP, although it did reduce the levels of GSH (P < 0.05). In addition, exercise increased CK, AST, and XO activities, although it did not change the values for hypoxanthine or UA. Green tea reduced the postexercise concentration of LH and increased the values of total polyphenols, GSH, and FRAP. GT also inhibited a significant rise in CK and XO activities induced by exercise. Furthermore, GT decreased the AST activity and hypoxanthine and UA concentrations before and after exercise. The assessment of food consumption revealed that the participants had an unbalanced diet, particularly in relation to vitamin E and carotenoids. Conclusion Consumption of GT, a beverage rich in polyphenols, may offer protection against the oxidative damage caused by exercise, and dietary guidance for sports participants should be emphasized.

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Author: Tzung-Hsun Tsai and Tsung-Hsien Tsai and You-Chia Chien and Chi-Wei Lee and Po-Jung Tsai

The antimicrobial activity against cariogenic bacteria, total antioxidant capacity and phenolic constituents of methanolic extracts from 11 herbs were investigated and compared with those of green tea (Camellia sinensis). Among the 12 tested herbs, eight herbal extracts could inhibit the growth of Streptococcus sanguinis. Jasmine, jiaogulan, and lemongrass were the most potent, with minimum inhibitory concentrations (MIC) of 1 mg/ml, while green tea was less effective, with a MIC of 4 mg/ml. Among them, only rosemary could inhibit the growth of S. mutans at a MIC of 4 mg/ml. Total antioxidant capacities of herbal extracts were analyzed by three different assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging activity, trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC). Regardless of the assays used, green tea exhibited the highest antioxidant capacity, followed by osmanthus. Wide variations in total phenolics and total flavonoids of herbal tea extracts were observed. Chlorogenic acid was detected in high amount in honeysuckle and duzhong. These data suggest that rosemary is a potent inhibitor of oral streptococci, and green tea and osmanthus may be effective potential sources of natural antioxidants.

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Author: S. Takami and T. Imai and M. Hasumura and Y.-M. Cho and J. Onose and M. Hirose

Author: Christian H. Coyle and Brian J. Philips and Shelby N. Morrisroe and Michael B. Chancellor and Naoki Yoshimura

Genitourinary tract inflammation/ailments affect the quality of life and health of a large segment of society. In recent years, studies have demonstrated strong antioxidant effects of green tea and its associated polyphenols in inflammatory states. This in vitro study examined the antioxidant capabilities (and putative mechanisms of action) of green tea extract (GTE), polyphenon-60 (PP-60, 60% pure polyphenols), (−)-epicatechin-3-gallate (ECG) and (−)-epigallocatechin-3-gallate (EGCG) in normal/malignant human bladder cells following catechin treatment ± 1 mM H2O2 (oxidative agent). Cell viability, apoptosis and reactive oxygen species (ROS) formation were evaluated. Our results showed that H2O2exposure significantly reduced normal (UROtsa) and high-grade (TCCSUP, T24) bladder cancer (BlCa) cell viability compared with control-treated cells (p < 0.001). No affect on low-grade RT4 and SW780 BlCa cell viability was observed with exposure to H2O2. Compared to H2O2-treated UROtsa, treatment with PP-60, ECG and EGCG in the presence of H2O2 significantly improved UROtsa viability (p < 0.01), with strongest effects evoked by ECG. Additionally, though not as effective as in UROtsa cells, viability of both high-grade TCCSUP and T24 BlCa cells, in comparison to H2O2-treated cells, was significantly improved (p < 0.01) by treatment with PP-60, ECG, and EGCG in the presence of H2O2. Overall, our findings demonstrate that urothelium cell death via H2O2-induced oxidative stress is mediated, in part, through superoxide (O2−">;), and potentially, direct H2O2 mechanisms, suggesting that green tea polyphenols can protect against oxidative stress/damage and bladder cell death.

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Author: Naghma Khan and Hasan Mukhtar

Tea ranks second only to water as a major component of fluid intake worldwide and has been considered a health-promoting beverage since ancient times. For the past two decades, we and others have been investigating the potential cancer preventive and therapeutic effects of green tea and its polyphenolic mixture termed GTP. It has become clear that much of these effects of GTP are mediated by its most abundant catechin, epigallocatechin gallate (EGCG). Large amount of encouraging data from in vitro and animal models has emerged making clear that green tea is a nature’s gift molecule endowed with anticancer effects. Epidemiological and geographical observations suggest that these laboratory data may be applicable to human population. Clinical trials of GTP, especially in prostate cancer patients have yielded encouraging results. This article briefly reviews properties of GTP, especially EGCG with reference to multitargeted therapy of cancer.

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